tweak-wrapper: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/tweak-wrapper - from package: tweak

You may install the required package with command apt-get install {package}

Error in other languages:
tweak-wrapper: bevel nie gevind nie
tweak-wrapper: comandă negăsită
tweak-wrapper: comando não encontrado
tweak-wrapper: commande introuvable
tweak-wrapper: command not found
tweak-wrapper: käsku ei ole
tweak-wrapper: không tìm thấy lệnh
tweak-wrapper: komanda nerasta
tweak-wrapper: Kommando nicht gefunden.
tweak-wrapper: kommandot finns inte
tweak-wrapper: komut yok
tweak-wrapper: nie znaleziono polecenia
tweak-wrapper: níor aimsíodh an t-ordú
tweak-wrapper: no se encontró la orden
tweak-wrapper: no s'ha trobat l'ordre
tweak-wrapper: opdracht niet gevonden
tweak-wrapper: parancs nem található
tweak-wrapper: perintah tidak ditemukan
tweak-wrapper: príkaz nenájdený
tweak-wrapper: příkaz nenalezen
tweak-wrapper: команда не найдена
tweak-wrapper: командата не е открита
tweak-wrapper: 命令找不到
tweak-wrapper: コマンドが見つかりません